Arsenal captain Robin Van Persie believes Manchester City's problems this season started when they lost in dying seconds at Sunderland, and that was the time when everyone realized that they could be beaten.
City's swaggering start to the season came to an unexpected halt when Dong-Won Ji scored an offside goal three minutes into injury time on the New Year's Day to give Sunderland three points.
The Dutch striker is determined to secure third place, and end City's title dream on Sunday by firing his side to victory at the Emirates.
Van Persie also agrees with City boss Roberto Mancini's assessment that his side's quest to be champions will be all over if rivals United beat QPR and they then lose in North London.
"They had their first real setback away at Sunderland when Dong-Won Ji scored an offside goal three minutes into injury time. It was New Year's Day and a massive shock. Everyone suddenly thought, 'Hey, they are beatable after all!'" The Sun quoted Van Persie, as saying.
"So, for me, that was the moment it all turned around for them. Before that, they were unstoppable. They were beating everyone in style. But since then they have been having a really hard time and Sunday's match is now a must-win for them. They just can't afford to lose," he added.
"It's a must-win game for us too because we want to finish the season in third to clinch automatic qualification for the Champions League," he said. (ANI)